[es6] implement spread calls

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index e43f565c3cff7b1ce0b228c2e605f0061b9a461e..0a0e12a8f8bbaaf96211e8af5ea7b3ab0af8a13b 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -181,6 +181,7 @@ DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony fetaures")
 DEFINE_IMPLICATION(harmony, es_staging)
 DEFINE_IMPLICATION(es_staging, harmony)
 
+
 // Features that are still work in progress (behind individual flags).
 #define HARMONY_INPROGRESS(V)                                           \
   V(harmony_modules, "harmony modules (implies block scoping)")         \
@@ -193,7 +194,9 @@ DEFINE_IMPLICATION(es_staging, harmony)
   V(harmony_unicode, "harmony unicode escapes")                         \
   V(harmony_unicode_regexps, "harmony unicode regexps")                 \
   V(harmony_computed_property_names, "harmony computed property names") \
-  V(harmony_rest_parameters, "harmony rest parameters")
+  V(harmony_rest_parameters, "harmony rest parameters")                 \
+  V(harmony_spread, "harmony spread operator")                          \
+  V(harmony_spreadcalls, "harmony spread-calls")
 
 // Features that are complete (but still behind --harmony/es-staging flag).
 #define HARMONY_STAGED(V)                                                 \
@@ -238,7 +241,8 @@ DEFINE_IMPLICATION(harmony_modules, harmony_scoping)
 DEFINE_IMPLICATION(harmony_classes, harmony_scoping)
 DEFINE_IMPLICATION(harmony_classes, harmony_object_literals)
 DEFINE_IMPLICATION(harmony_unicode_regexps, harmony_unicode)
-
+DEFINE_IMPLICATION(harmony_spreadcalls, harmony_spread)
+DEFINE_IMPLICATION(harmony_spread, harmony_spreadcalls)
 
 // Flags for experimental implementation features.
 DEFINE_BOOL(compiled_keyed_generic_loads, false,